Question

1-4•[-5•(x-2)]=21
5(x-2)-7(x+3)=0
(x+3)(x-7)=0
(-2x+6)(x+3)=0​

Answer 1

Răspuns:

Explicație pas cu pas:

1-4•[-5•(x-2)]=21

4•[-5•(x-2)] = 1 - 21 = -20

-5•(x-2) = -20 : 4 = -5

x - 2 = -5 : (-5) = 1

x = 1 + 2 = 3

____________________

5(x-2)-7(x+3)=0

5x - 10 - 7x - 21 = 0

-2x - 31 = 0

2x = -31

x = -31/2

_____________________

(x+3)(x-7)=0

x + 3 = 0 ⇒ x = -3

x - 7 = 0 ⇒ x = 7

______________________

(-2x+6)(x+3)=0​

-2x + 6 = 0 ⇒ 2x = 6 ⇒ x = 6 : 2 = 3

x + 3 = 0 ⇒ x = -3